The present applicant formerly proposed a vacuum press apparatus for effecting press adhesion under heating at high vacuum while evacuation is performed, in bonding IC cards, print circuit boards, polarization lenses. See JP-A-2002-96199. In this apparatus, however, a sliding frame to form the isolation chamber is directly contacted with a jig containing a heater. Since the heat-withstanding temperature of seal packings (O-rings or the like) provided in the sliding frame is in a low temperature range of around 200° C. Therefore, such an apparatus cannot be used in case that pressing needs to be done under high temperatures higher than that temperature.
Under the circumstances, heretofore, high-temperature pressing needed to be done in a large-size fixed vacuum apparatus having an gas-tight on/off door provided with a seal packing containing a heat-resistant grease. Thus, since products need to be put into and removed from the apparatus having high interior temperature via the door, it was troublesome and very dangerous.
Further, recently, when a polarization film is to be bonded on a liquid crystal panel or a touch panel, it is necessary to prevent large press pressure from being applied onto the liquid crystal panel sealed between thin glass plates. Furthermore, when a film or a non-hardened green ceramic sheet is to be bonded onto a thin hollow frame body, a soft bonded material is deformed by pressing pressure. Thus, there is an increasing demand that bonding is effected under extremely low pressure. In addition, with progress in electronic devices, need to form laminated films each consisting of plural thin functional films has been increasing. In the case of the laminated films for condensers, if the laminated film is pressed under large press pressure until the materials are not uniformly heated, an interior vapor deposited film may be cracked or an uneven adhesive may correspondingly deform an opposing film. Therefore, it has been demanded that the laminated film is pressed under low pressure and then adhered fast by increasing the press pressure after heating.
Further, according to the conventional heating-type vacuum press bonding apparatus, workpieces to be processed need to be fed onto and removed from a workpiece-receiving table in the state that upper and lower jigs are opened from each other. Since the upper and lower jigs are provided with high-temperature heaters in a heated state, there is a danger in working, such as burn injure because a space between them is small even in the opened state.
The present invention is aimed at a heating-type vacuum press apparatus which realizes forming an isolation chamber of a narrow space inside upper and lower jigs with high vacuum through operation of the press apparatus and pressing workpieces under heating at high temperatures, without using a large-size vacuum device in which workpieces are required to be charged and removed in the state that a door is opened every time even if the workpieces need to be pressed under vacuum at high temperatures of 300 to 400° C. The invention is also aimed at preventing damage of a seal packing of a wall constituting the isolation chamber.
It is another object of the present invention to provide a heating-type vacuum press apparatus which enables pressing under heating at extremely low pressure to low press pressure.
It is a further object of the present invention to provide a heating-type vacuum press apparatus which enables workpiecs to be fed onto and removed from a receiving table without working danger such as burn injury.
The present inventor has made repeated investigations, and discovered that further improvement would be preferred.
That is, when a workpiece is to be pressed under application of pressure in the vacuum heating apparatus in which the isolation vacuum chamber is to be formed, thrusting force for press processing is applied onto the workpiece. Since a large weight is applied to upper members of the isolation chamber-constituting members, the heater, a press plate, etc. under vacuum, the apparatus is suitable for pressing under high pressure as in a case where a considerable weight needs to be applied onto the workpiece.
However, as to materials to be bonded which are likely to be cracked or damaged, as in cases where films are to be bonded to film condensers, film cells, touch panels or liquid display panels or polarizing films are to be bonded onto liquid crystal glasses, press deformation is hated and high pressure pressing is hated in the state that an adhesive or a curing agent is not thermally fused. In a case of bonding soft half-cured green ceramic sheets together, there occurs a problem that the films are thinly stretched by pressing under high pressure as in a case with clay and thus a uniform thickness is not attained. Therefore, pressing needs to be performed under heating at an extremely subtle low pressure.